An engine generates useful power by taking in air and fuel and creating power in a combustion reaction within a closed cylinder. The power of the combustion in the closed cylinder creates useful power by transmitting force to an engine crankshaft. A throttle in an engine regulates the amount of air that an engine may take in using an applied vacuum source. When the throttle position is completely open, the engine takes in the most amount of air by reducing intake air manifold pressure. Fuel is injected into the engine. More combustion occurs in a closed cylinder. More power is generated. Conversely, when the throttle position is completely closed, an engine takes in the least of air it can take in using an applied vacuum source from the intake air manifold. The minimum amount of air and fuel is combusted in a closed cylinder. The engine generates the least amount of power that the engine can generate.
Even a small leak of any kind in an engine detracts from the maximum amount of power that an engine can generate. The effect of an engine gas leak may be easily perceived by the human senses as sub-optimal engine performance. When the engine is the power source in a motorized apparatus controlled by a human, the human experience may be reduced power delivery from the engine relative to engine performance prior to development of a gas leak.
Liquid leaks are usually positive pressure leaks. Pressure behind a liquid causes a leak to form when the liquid seeks out a lower pressure region. Some liquid leaks are relatively easy to observe and repair by sealing. Gas leaks may be positive pressure or negative pressure. Finding a gas leak, whether positive pressure or negative pressure, may be relatively more difficult than a liquid leak. A gas expands to fill available space rather than accumulate, as a leak from a liquid usually will. A gas may be colorless, odorless, or both, and more difficult to detect. A gas vacuum leak may be yet more difficult to detect for the reasons mentioned above.
Finding and repairing one or more gas leaks in an engine can return an engine to optimal performance. Finding and repairing one or more gas leaks in an engine in a short period of time can return an engine to optimal performance in a short period of time.
Silicone-based compositions are known in general for sealing liquid leaks. Silicone-based compositions are materials used to prepare gaskets for engines, including oil pan gaskets and engine head gaskets. Silicone room temperature vulcanizate (RTV) compositions are used in a variety of applications, including engine-type applications. Silicone-based “form-in-place” gaskets for engines exist.
Silicone-based materials have been used to seal positive pressure liquid leaks in some applications. Silicone-based materials are known to exhibit relatively high contact angles with surfaces relative to other types of materials. There exists a need for other materials to seal engine gas leaks.